Paul Singh did some work on the humidifier on recommendation of the manufacturer. Overall, he charged me $1000 to do 'routine maintenance' without addressing specific issues, namely that the fill and drain valves were full of calcium and needed to be replaced as suggested by the distributor. So I went through many hours of trying to figure out why the thing was still not working consistently after the service call, with some telephone support from Paul. Finally, he asked how handy I was... And whether I wanted to order the valves myself and replace them myself. Well, that's exactly what I ended doing and presto, the thing has worked smoothly ever since. It remains to be seen why I burnt $1000 on other general service, which was probably not even necessary. Hesitate to recommend.